# [ANSYS Meshing] Dynamic meshing of a deforming body

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 October 16, 2016, 06:38 Dynamic meshing of a deforming body #1 Member   Join Date: Aug 2016 Posts: 43 Rep Power: 9 Hello, I have a mathematical formula that gives the coordinates of a deforming 2D body, and I would like to use them in order to create the body and the dynamic meshing around it , how should I approach it ? does it require a UDF ? Thanks

 October 17, 2016, 02:16 #2 Senior Member   Paritosh Vasava Join Date: Oct 2012 Location: Lappeenranta, Finland Posts: 732 Rep Power: 22 You will certainly need UDF. The UDF setup and macro usage will depend on how the boundary is moving and deforming. Re-meshing could be handled by setting up dynamic mesh zone. Without any technical details about the problem, it is very difficult to help you. Perhaps you can go through some dynamic mesh tutorials such as check valve simulation using Dynamic Meshes, Simulating a Gear Pump Using Dynamic Mesh with 2.5D Re-meshing, Using a UDF to Control the Dynamic Mesh of a Flexible Oscillating Membrane etc.

 October 17, 2016, 06:46 #3 Member   Join Date: Aug 2016 Posts: 43 Rep Power: 9 Thanks for the answer, the problem is as follow , I have two curves that makes up a body upper and lower surface, so the geometry is defined by two equations have parameters changing by time so the geometry will deform. The issue is how to do the meshing around the geometry where all I have are the equations and therefore the coordinates in each time time step. All the tutorials mentioned start from a given defined geometry imported into the mesher then it will be be rotated or deformed. Is it more clear ?

October 18, 2016, 03:53
#4
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Paritosh Vasava
Join Date: Oct 2012
Location: Lappeenranta, Finland
Posts: 732
Rep Power: 22
Quote:
 Originally Posted by aero_cfd All the tutorials mentioned start from a given defined geometry imported into the mesher then it will be be rotated or deformed.
The UDF for Flexible Oscillating Membrane tutorial has a part where an interface is deforming according to some equation and the mesh around the deforming interface is re-meshed. You can try to introduce a time dependent equation instead and see how it goes. Macros such as PREVIOUS_TIME, CURRENT_TIME, CURRENT_TIMESTEP etc. could be used to get time information.

 October 28, 2016, 06:36 #5 Member   Join Date: Aug 2016 Posts: 43 Rep Power: 9 is it possible to get this tutorial with the files . i wasn't able to find the files and UDF ?

 October 29, 2016, 07:13 #6 Member   Join Date: Aug 2016 Posts: 43 Rep Power: 9 I already got the files and went through the tutorial. in the C file you have the DEFINE_GEOM function , does it define the plane or the plane is already defined when you draw the geometry then you mesh it? because it seems this is the case, then what does the DEFINE_GEOM do ?

 October 31, 2016, 05:46 #7 Senior Member   Paritosh Vasava Join Date: Oct 2012 Location: Lappeenranta, Finland Posts: 732 Rep Power: 22 In this tutorial DEFINE_GEOM defines the plane which is represented via an equation. In the tutorial the UDF is applied to the top wall. The macro causes the moving mesh to slide on the top wall and the near by nodes to project on the wall in order to keep the shape of the wall intact. You can make an animation of the moving mesh and you will notice this. I hope this helps.

April 16, 2019, 04:11
#8
New Member

vicky
Join Date: Sep 2014
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Quote:
 Originally Posted by aero_cfd I already got the files and went through the tutorial. in the C file you have the DEFINE_GEOM function , does it define the plane or the plane is already defined when you draw the geometry then you mesh it? because it seems this is the case, then what does the DEFINE_GEOM do ?

 Tags define grid motion, deformation, dynamic meshing